Abstract: A gravure method for applying a discrete patch (12) of uniform coating to a moving web (14) includes defining a nip area (20) between a gravure roller (16) and a backing roller (22), moving the gravure roller to the nip to a precise lengthwise location on the web, and moving the gravure roller from the nip. The method is improved by controlling the speed of movement of the gravure roller to the nip, and controlling the speed of movement of the gravure roller from the nip thereby producing a discrete patch.

Abstract: A method and apparatus is disclosed for gravure coating a liquid reactive with the atmosphere onto a web. The gravure apparatus comprises an engraved gravure cylinder, an impression roller backing the web and pressing it onto the gravure cylinder to form a nip, a curtain or jet formation means to wet the surface of the gravure cylinder, and a doctor blade means for wiping excess coating liquid from the surface of the gravure cylinder prior to the nip. A shroud encompassing the gravure cylinder and the curtain or jet formation means creates a first zone between the nip and a partitioning baffle extending from the shroud, a second zone between the partitioning baffle and the doctor blade means, and a third zone between the doctor blade means and the nip. A gas non-reactive with the coating liquid is supplied to each zone by a gas distribution means such that the reaction rate of the coating liquid with the atmosphere is greatly reduced and the curtain or jet is not disrupted.

Abstract: A coating method and apparatus are taught for coating a liquid composition onto a surface of a moving web. A coating hopper for delivering the liquid composition to the surface of the moving web is provided with a rotatable backing roller. The moving web is wrapped around a portion of the rotatable backing roller with the rotatable backing roller supporting the moving web through a dynamic wetting line. The rotatable backing roller includes a plurality of circumferential grooves therein at a groove pitch of at least two per millimeter. An electrostatic field generated across the gap between the moving web and the liquid composition immediately prior to the dynamic wetting line. The method and apparatus permit either coating at a higher speed or higher viscosity than may be achieved in the prior art, or greatly reduced groove line nonuniformity at a given coating speed and viscosity.

Abstract: A coating method and apparatus are taught for coating a liquid composition onto a surface of a moving web. A coating hopper for delivering the liquid composition to the surface of the moving web is provided with a rotatable backing roller. The moving web is wrapped around a portion of the rotatable backing roller with the rotatable backing roller supporting the moving web through a dynamic wetting line. The rotatable backing roller includes a plurality of circumferential grooves therein at a groove pitch of at least two per millimeter. An electrostatic field generated across the gap between the moving web and the liquid composition immediately prior to the dynamic wetting line. The method and apparatus permit either coating at a higher speed or higher viscosity than may be achieved in the prior art, or greatly reduced groove line nonuniformity at a given coating speed and viscosity.

Abstract: An inexpensive and versatile method for creating a curtain of continuously adjustable width for the purpose of coating portions of a receiving surface to form one or more layers of coating composition comprises a distributor which has a horizontal lip from which the layers detach to form a free-falling curtain. A trough adjacent and below the lip is provided to intercept and divert some portion of the curtain and an edge guide is provided to maintain the width of the remaining portion of the free-falling curtain.

Abstract: A hopper bar having a longitudinal channel formed in the portion of the bar which normally would support a coating lip wherein a wall of the channel is a precision cylindrical locating pin, and has a replaceable hopper lip element, formed to fit within the channel, is provided with a precision round bushing for receiving the locating pin such that upon assembly of the element to the hopper there is no offset significant to the coating process between the slide surface of the hopper bar and the slide surface of the lip element. The lip element may be attached to the hopper wall along the remainder of their mutual length by either bolts or magnets to permit independent longitudinal thermal expansion of the hopper bar and lip element.

Abstract: An apparatus for coating surfaces consists of a basin, open to the atmosphere, divided into two channels by a wall running perpendicular to the coating direction. Liquid is supplied to the primary channel, the channel farther from the curtain. A continuous, adjustable gap between the dividing wall and the bottom of the basin offers resistance to flow but passes the coating composition from the primary to the secondary channel. The secondary channel has an edge that is horizontal and relatively low so that the coating composition overflows it to form a free-falling curtain. The dividing wall, by providing flow resistance, assists in distributing the supplied coating composition along the length of the primary channel, and reduces any flow disturbances caused by the entering coating composition. The secondary channel promotes additional evening of the flow distribution before the curtain forms.